Re: pgBufferUsage.blk_{read|write}_time are zero although there are pgBufferUsage.local_blks_{read|written}

Hi,

On Tue, 10 Oct 2023 at 03:54, Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>
> In ~14, as far as I can see blk_write_time is only incremented for
> shared buffers. FWIW, I agree that we should improve these stats for
> local buffers but I am not on board with a solution where we'd use the
> same counter for local and shared buffers while we've historically
> only counted the former, because that could confuse existing
> monitoring queries. It seems to me that the right solution is to do
> the same separation as temp blocks with two separate counters, without
> a backpatch. I'd like to go as far as renaming blk_read_time and
> blk_write_time to respectively shared_blk_read_time and
> shared_blk_write_time to know exactly what the type of block dealt
> with is when querying this data, particularly for pg_stat_statements's
> sake.

Yes, that could be a better solution. Also, having more detailed stats
for shared and local buffers is helpful. I updated patches in line
with that:

0001: Counts extends same way as a write.
0002: Rename blk_{read|write}_time as shared_blk_{read|write}_time.
0003: Add new local_blk_{read|write}_time variables.

Regards,
Nazir Bilal Yavuz
Microsoft